Is it worth buffing bad Unique Units if they are from a good civ?

Most people would agree that units like the elephant archer aren’t good, and might say they could use a buff. But do Indians need a buff? Do good civs with bad UUs like the Khmer and slavs really deserve to be even better?

Huns used to be the best civ in the game and their UU was trash in AoC. I think its cool that some civs have more situational unique units, while others (like Mayans or mongols for example) rely heavily on their Unique unit and therefore, rely on stone in the long game. I feel like this makes the civs feel more different from each other. But also having a completely trash unique isn’t fun either, it feels like the civ doesnt even have one.

So what unique units need buffs? You could also nerf the civ at the same time to compensate for it.